The present invention relates to a general purpose interface to a Fibre Channel array controller, more particularly to a gigabit interface converter (GBIC) or a gigabit link module (GLM) channel adapter, and to the use of a channel controller with associated general GBIC/GLM adapters to provide an ultra-high bandwidth bus.
Enterprise resource planning systems and other sophisticated corporate data processing systems have gained substantial importance in recent years. Specifically, many corporate management theories posit that the success of an organization is directly related to the ability to gather and process enterprise information in an efficient and organized manner. To fulfill these goals, certain software companies have produced information management products such as RP/3 and the like. These types of software systems manage enormous amounts of information. Management of inventory levels, customer purchasing information, accounting data, employment information, and various other databases requires significant storage capacity. In addition, e-commerce has placed a premium upon transferring ordinary business operations to electronic work flows, thereby creating further storage capacity requirements. In addition, increased processing speed and capacity places greater demands upon storage resources.
Disk arrays have been designed to address these storage requirements. An exemplary disk array system is described in commonly assigned U.S. Pat. No. 5,392,244, entitled xe2x80x9cMEMORY SYSTEMS WITH DATA STORAGE REDUNDANCY MANAGEMENT,xe2x80x9d the disclosure of which is incorporated herein by reference. In essence, a disk array is a system that utilizes a number of discrete disks and interfaces with a host system or systems in such a manner that the assemblage of discrete disks appears as a single disk system. Disk arrays present numerous advantages. For example, disk arrays are highly redundant. If a particular discrete disk fails, the remaining portion of the disk array remains in operation. Moreover, disk arrays permit data mirroring, i.e. the same data may be stored upon more than one disk to provide greater redundancy against discrete disk failure. Accordingly, the probability of failure of the entire disk array is much lower than integrated storage systems.
Moreover, known disk array systems are designed to operate in a Fibre Channel environment. The Fibre Channel communication protocols are somewhat similar to the well-known Small Computer System Interface (SCSI) scheme, except for several differences. SCSI is a parallel interface standard used by various personal computers for attaching peripheral devices to computers. The Fibre Channel approach utilizes a mapped protocol to communicate frames, instead of individual bytes. Moreover, the Fibre Channel approach does not utilize parallel communication path connections. Instead, the Fibre Channel environments utilize serial communication channels to provide various system architectures, such as point-to-point, arbitrated loop, and crosspoint switched topologies. The serial communication approach simplifies system configuration. Specifically, the in-bound cable for one device in a Fibre Channel environment is the out-bound cable for a preceding device (either another independent unit or a fabric circuit switch). The fiber may comprise either an optical fiber cable or a twin-axial copper cable. For the remaining material, the term xe2x80x9cfiberxe2x80x9d shall be interchangeably utilized to mean either a fiber optical medium or a twin-axial copper cable. Also, it should be noted that Fibre Channel systems provide very high data communication rates. In fact, gigabit communication rates are possible. Fibre Channel systems rely upon intermediate devices to propagate information accurately between source and destination devices. Since the Fibre Channel architecture utilizes this approach, Fibre Channel systems limit the number of devices that may be present upon the system. This limitation is imposed to reduce latency and improve data communication rates.
Since there is an inherent limitation upon the number of devices present upon a Fibre Channel system, disk arrays operating upon a Fibre Channel system do not connect each individual disk unit to the external Fibre Channel system. Instead, a Fibre Channel disk array integrates the Fibre Channel in-bound and out-bound cables in a backplane. The Fibre Channel disk arrays further comprise a controller unit to arbitrate or manage communication between the discrete disk units and the Fibre Channel environment. The operating principles of an array controller is described in commonly assigned U.S. Pat. No. 5,471,640, entitled xe2x80x9cPROGRAMMABLE DISK ARRAY CONTROLLER HAVING N COUNTERS FOR N DISK DRIVES FOR STRIPPING DATA WHERE EACH COUNTER ADDRESSES SPECIFIC MEMORY LOCATION BY A COUNT OF N,xe2x80x9d the disclosure of which is incorporated herein by reference. The controller unit may provide a predetermined number of disk bays for connecting individual disk units. Thereby, the discrete disk units communicate directly with the controller unit. The controller unit assembles information received via the disk bays from the drives for communication in the forward direction over the fiber channel. Similarly, the controller unit separates data communicated in the reverse direction for distribution to the particular discrete drive units via appropriate disk bays. The controller unit further manages the discrete disk units in a manner that the plurality of units appears as a single disk. The controller unit implements mirroring tasks to provide for greater redundancy. Also, the use of Fibre Channel protocols permits efficient communication of data from discrete disk units to destination devices on the Fibre Channel system. Specifically, Fibre Channel protocols have demonstrated high bandwidth capability for large file transfers.
This architecture is quite useful to provide large storage capacity in an efficient and reliable fashion. However, the architecture of such disk array systems is specifically designed for a single purpose-data storage upon multiple discrete disk units. Moreover, the architecture provides very limited scalability. Specifically, the architecture limits the addition of discrete disk units to a predetermined number. At the present time, additional storage requirements must be fulfilled by providing a separate disk array system which obviously entails substantial expense. Also, the controller unit is singularly designed to interface with discrete disk units via the disk bays. Since the controller unit utilizes a specific interconnect, it is not possible to connect other devices via the disk bays.
The present invention provides an interface to facilitate a scalable and cost-effective disk array system. By doing so, the present invention simplifies operating system compatibility issues by facilitating scalable data storage. The present invention provides a general purpose interface to permit connection of heterogeneous devices to a Fibre Channel controller via plug-in connections. Also, the present invention facilitates connection of a plurality of heterogenous devices to a Fibre Channel system via a controller in a manner that the plurality of devices appears from a system perspective as a single device. Moreover, the present invention provides a general interface to a Fibre Channel controller to provide an ultra-high speed bus.
The present invention is directed to a general purpose interface to a Fibre Channel controller. The system provides a dual or greater slot interface to a single bay of a fiber channel system. The interface may preferably comprise two slots utilizing either a gigabit interface converter (GBIC) or a gigabit link module (GLM) for both slots. By providing a plurality of slots, the present invention permits scalable addition of devices to the Fibre Channel controller. The interface does not simply double the interface capacity of the Fibre Channel controller. Instead, individual interfaces may be serially connected. Thus, the interfaces permit exponential expansion of capacity to a single port of the Fibre Channel controller. Moreover, the present invention permits connection of heterogenous devices to the Fibre Channel controller in addition to discrete disk units. For example, the interface may permit connection of CD-ROM drives, tape units, networking cards, optical drives, and/or the like. In alternate embodiments, the present invention allows connection via other interfaces, such as SCSI interfaces, WDM interfaces, RS-232 interfaces, and/or the like.
Also, the present invention realizes that Fibre Channel controllers are not limited to disk array systems. By designing general purpose interfaces to a Fibre Channel controller, the present invention permits a Fibre Channel controller and its fiber channels to serve as an ultra-high speed bus. Specifically, any type of device may be connected to the controller. Thus, Fibre Channel controllers may provide the same capabilities of an ordinary bus with significantly higher bandwidth capability in accordance with the present invention.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.